From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0104C3F2CD for ; Wed, 4 Mar 2020 05:52:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C44B2146E for ; Wed, 4 Mar 2020 05:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726254AbgCDFw5 (ORCPT ); Wed, 4 Mar 2020 00:52:57 -0500 Received: from foss.arm.com ([217.140.110.172]:56118 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725271AbgCDFw5 (ORCPT ); Wed, 4 Mar 2020 00:52:57 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E08EF30E; Tue, 3 Mar 2020 21:52:55 -0800 (PST) Received: from [10.163.1.88] (unknown [10.163.1.88]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DCC5B3F6CF; Tue, 3 Mar 2020 21:52:48 -0800 (PST) Subject: Re: [RFC 2/3] mm/vma: Introduce VM_ACCESS_FLAGS To: Vlastimil Babka , linux-mm@kvack.org Cc: Russell King , Catalin Marinas , Mark Salter , Nick Hu , Ley Foon Tan , Michael Ellerman , Heiko Carstens , Yoshinori Sato , Guan Xuetao , Dave Hansen , Thomas Gleixner , Rob Springer , Greg Kroah-Hartman , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org, nios2-dev@lists.rocketboards.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org References: <1583131666-15531-1-git-send-email-anshuman.khandual@arm.com> <1583131666-15531-3-git-send-email-anshuman.khandual@arm.com> <52b4565f-2dab-c3e5-ead8-d76258f43a10@suse.cz> From: Anshuman Khandual Message-ID: Date: Wed, 4 Mar 2020 11:22:46 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <52b4565f-2dab-c3e5-ead8-d76258f43a10@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/03/2020 11:18 PM, Vlastimil Babka wrote: > On 3/2/20 7:47 AM, Anshuman Khandual wrote: >> There are many places where all basic VMA access flags (read, write, exec) >> are initialized or checked against as a group. One such example is during >> page fault. Existing vma_is_accessible() wrapper already creates the notion >> of VMA accessibility as a group access permissions. Hence lets just create >> VM_ACCESS_FLAGS (VM_READ|VM_WRITE|VM_EXEC) which will not only reduce code >> duplication but also extend the VMA accessibility concept in general. >> >> Cc: Russell King >> CC: Catalin Marinas >> CC: Mark Salter >> Cc: Nick Hu >> CC: Ley Foon Tan >> Cc: Michael Ellerman >> Cc: Heiko Carstens >> Cc: Yoshinori Sato >> Cc: Guan Xuetao >> Cc: Dave Hansen >> Cc: Thomas Gleixner >> Cc: Rob Springer >> Cc: Greg Kroah-Hartman >> Cc: Andrew Morton >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-c6x-dev@linux-c6x.org >> Cc: nios2-dev@lists.rocketboards.org >> Cc: linuxppc-dev@lists.ozlabs.org >> Cc: linux-s390@vger.kernel.org >> Cc: linux-sh@vger.kernel.org >> Cc: devel@driverdev.osuosl.org >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual > > Dunno. Such mask seems ok for testing flags, but it's a bit awkward when > initializing flags, where it covers just one of many combinations that seem > used. But no strong opinions, patch looks correct. Fair enough. The fact that it covers only one of the many init combinations used at various places, is indeed a good point. The page fault handlers does start with VMA flags mask as VM_ACCESS_FLAGS, hence will keep them and drop other init cases here.